Guidewires for vascular catheters are commonly used in angioplasty procedures relating to the coronary arteries and elsewhere. An example of such a guidewire is illustrated by Box U.S. Pat. No. 4,846,186. There, it is shown that the distal end of the guidewire carries a coil spring which may be nine or ten inches long as specifically described in the Box patent. Within the coil spring, the guidewire is tapered down to a relatively narrow width. A distal tip portion is attached by brazing to the end of the narrow-diameter distal guidewire section, which tip retains the distal end of the spring.
It is conventional for the proximal end of the guidewire to simply terminate with a flat end.
Guidewires are typically very narrow, having a diameter in their central, largest-diameter portion of about 0.01 to 0.02 inch. Thus, even though the proximal end of the guidewire may be squared off and not equipped with a point, at that narrow diameter the guidewire has a considerable capability of punching through a rubber glove and sometimes injuring the hand, if the surgeon is not careful in his operation. Of course any breach of a biological barrier as is provided by the rubber gloves is most undesirable, raising a risk of the spread of disease between the physician and the patient, especially in the situation of a vascular catheter guidewire, where blood can be present outside of the patient's body, and on the guidewire.
It is not a satisfactory solution to place an enlarged, proximal tip on the proximal end of the guidewire, because such an enlarged tip, while it would help to reduce accidental penetration of gloves by the guidewire proximal end, would interfere with the use of torquing devices. These devices are used for rotating the guidewire during the procedure of inserting the guidewire distal tip into a desired artery while controlling the guidewire from the proximal end thereof.
Guidewires such as that disclosed in Amplatz, U.S. Pat. No. 4,991,602 have blunt tips on the ends of tapered guidewire portions, but the tips are not substantially larger than the diameter of the main body of the guidewire. Furthermore, when one attempts to push such a guidewire from its end, either accidentally or purposely, such a wire tip is likely to collapse and kink with such pushing, which is of course undesirable.
By this invention, the above problems are addressed in such a manner as to provide an improved guidewire having a proximal end which cannot damage the surgeon's glove or hand as the wire is being manipulated, pushed, or the like. Nevertheless, the guidewire of this invention is capable of being attached at its proximal end to a currently available torquing device for rotation of the wire, to assist in the steering process as the wire is advanced.